The illustration below, taken from the periodic table, provides information about the element calcium (Ca).

Transcription

1 Test Name: Copy of Grade 8 Unit 2 Pretest Test Id: Date: 10/20/2017 Section 1 The illustration below, taken from the periodic table, provides information about the element calcium (Ca). Where would the element with atomic number 19 be placed on the periodic table? 1. A. above calcium B. below calcium C. to the left of calcium D. to the right of calcium Which particles are found in the nucleus of an atom? 2. A. protons and electrons B. electrons and neutrons C. protons and neutrons D. protons, neutrons, and electrons The picture show the models that four students each constructed out of marshmallows and gumdrop candies to illustrate the difference between atoms and molecules.

2 Which model is the most effective? 3. A. Model 1 is the most effective because it shows that elements are always organized in orderly arrays. B. Model 2 is the most effective because it shows that atoms are bound to each other and molecules are made of a single element. C. Model 3 is the most effective because it shows that molecules can be made out of more than one type of atom. D. Model 4 is the most effective because it shows that both atoms and molecules can be composed of different elements. The formula for baking soda is given. NaHCO 3 This formula indicates that a molecule of baking soda contains 4. A. 1 hydrogen atom, 1 sodium atom, 3 carbon atoms, and 3 oxygen atom. B. 1 sodium atom, 1 hydrogen atom, 1 carbon atom, and 3 oxygen atoms. C. 1 potassium atom, 1 helium atom, 1 carbon atom, and 1 oxygen atom. D. 1 carbon atom, 1 helium atom, 1 calcium atom, and 3 oxygen atoms. Look closely at the illustration below, which shows a part of the periodic table.

3 Which two elements have properties that are the most similar? 5. A. C and F B. He and Ne C. Al and Si D. N and S More than half of the elements on the periodic table are metals, most of which are 6. A. semiliquid at room temperature. B. liquid at room temperatures. C. gases at room temperature. D. solid at room temperature. The diagram shows a sample of matter undergoing some change. What kind of change is shown in the diagram? 7. A. elements breaking down into atoms B. molecules breaking down into atoms C. atoms breaking down into molecules D. elements breaking down into molecules

4 Select three of the following elements that most likely share properties with carbon. 8. A. platinum B. copper C. tin D. calcium E. silicon F. lead What is the minimum number of atoms needed to make a molecule? 9. A. 0 B. 1 C. 2 D. 3 Marcus discovered that sodium (Na) is found in Group 1, Period 3 on the periodic table. Where should Marcus look to find another element that has similar properties to those of sodium? 10. A. in Group 1 B. in Period 3 C. on the opposite side of the periodic table D. at elements whose symbols begin with the letter N Which three particles make up an atom? 11. A. protons, neutrons, and isotopes B. neutrons, isotopes, and electrons C. positives, negatives, and electrons D. protons, neutrons, and electrons Carbon monoxide is a simple compound of one carbon atom and one oxygen atom. What is the sum of atomic numbers for all the elements in carbon monoxide?

5 12. A. 28 B. 14 C. 6 D. 8 What is the smallest unit that defines an element? 13. A. plasma B. molecule C. compound D. atom When sodium is mixed with water, an explosion takes place. Based on its location on the periodic table, how will potassium behave with water? 14. A. Potassium, which shares similar properties with sodium, will explode in water. B. Potassium, which shares similar properties with sodium, will not explode in water. C. Potassium, which does not share similar properties with sodium, will explode in water. D. Potassium, which does not share similar properties with sodium, will not explode in water. Which statement about atoms and molecules is true? 15. A. atoms make up elements and molecules make up atoms B. atoms make up molecules and molecules make up elements C. atoms make up compounds and molecules make up elements D. atoms make up molecules and molecules make up compounds Two particles of oxygen bonded together is

6 16. A. an oxygen molecule. B. an oxygen compound. C. an oxygen atom. D. an oxygen mixture. A majority of the 118 elements on the periodic table are classified as 17. A. liquids. B. metals. C. metalloids. D. non-metals. If Elroy looks through a powerful electron microscope at atoms in a piece of matter, the atoms will appear to be which structures? 18. A. cubes B. cylinders C. pyramids D. spheres The diagrams show sulfur dioxide and neon. The diagrams most likely represent 19. A. one atom of sulfur dioxide and two atoms of neon. B. three atoms of sulfur dioxide and two atoms of neon. C. one molecule of sulfur dioxide and one molecule of neon. D. one molecule of sulfur dioxide and two molecules of neon.

7 What do group numbers on the periodic table identify? 20. A. The number of valence electrons in atoms. B. The total number of electrons in atoms. C. The number of protons in atoms. D. The number of neutrons in atoms. An element is 21. A. able to be separated. B. made up of only one type of atom. C. composed of different types of atoms combined together. D. always in a liquid state at room temperature. Read the passage about modeling clay. Steve uses clay to model the law of conservation of matter. First, he finds the mass of a ball of clay on a balance. Then, he molds the clay into a different shape without adding or removing clay. Finally, he finds the mass on a balance again. How will Steve's results show the law of conservation of matter? 22. A. The results will show that both the shape and the mass have changed. B. The results will show that the shape has changed, but the mass is the same. C. The results will show that changing the shape has changed the mass of the clay. D. The results will show that the larger the shape, the greater the mass. Rachel and Billy are conducting an experiment. The mass of their candle before burning was 7.0 grams. After burning the candle for six minutes, the mass went down to 5.5 grams. What can the students determine about the results of their experiment? 23. A. The law of conservation of mass cannot be applied over short periods of time. B. The law of conservation of mass does not apply to chemical changes like burning. C. The law of conservation of mass was broken because the mass of the candle decreased. D. The law of conservation of mass was not broken because the missing mass was released as smoke.

8 Which of the following states the law of conservation of mass? 24. A. In a chemical reaction, two compounds combine to form a new compound. B. In a chemical reaction, atoms are rearranged, and some join new molecules. C. Mass cannot be created or destroyed in a chemical reaction. D. Energy is neither created nor destroyed in a chemical reaction. You have reached the end of this section.